The Rayleigh-Taylor instability in stratified plasma has been
investigated in the presence of combined effect of horizontal and vertical
magnetic field. The linear growth rate has been derived for the case where
plasma with exponential density distribution is confined between two rigid
planes by solving the linear MHD equations into normal mode. Some special cases
have been particularized to explain the roles the variables of the problem play;
numerical solutions have been made and some stability diagrams are plotted and
discussed. The results show that, the growth rate depends on the horizontal and
vertical components of magnetic field and also depends on the parameter λ*=λLD (λ is constant and LD is the
density-scale length). The maximum instability happens at λ*=-0.5 and to get more stability model we select λ* such that it is different than λ*=-0.5. The
vertical magnetic field component have a greater effect than the horizontal
magnetic field component in the case of large wavelength, while in the case of
short wavelength, the horizontal magnetic field components have
greater effect than the vertical magnetic field component.
system needs irrigation and introduces new cultivars in new environments.
So the evaluation of varietal ecophysiological response to irrigation is a crucial
topic. For this reason it was planned a research on two cultivars, Coratina and
Arbequina, trained according to high-density system. In 2009 the irrigation
was conducted according to the conventional management by applying an
irrigation frequency of 4 days. The leaf water potentials reached values
similar to the limits reported for the recovery within 48 hours. However,
plants showed a leaf water status and gas exchange recovery just after 24
hours from watering. The results
highlighted some varietal differences: Arbequina showed a better response to irrigation, while Coratina performed
a higher water use efficiency by a lower leaf transpiration.
Escherichia coli RecA has been considered traditionally a cellular protein with multiple vital functions working to ensure the maintenance of integrity of genome in each individual bacterial cell as well as promoting swarming migration in collectivity. On the contrary, recently it has been described that RecA promotes cellular apoptotic-like death (ALD), a pathway of programmed cellular death (PCD). In fact, RecA has been dubbed as the major apoptotic executor in E. coli. From these studies, RecA emerges as a prototypical Gin/Gan protein that despite of their intrinsic vital and lethal anfi-funcionality becomes in a WISE factor: a Worker to Integrate Survival and Evolution in E. coli evolving populations living in community. Here, I provide a review of recent experimental and conceptual advances trying to understand these RecA’s antagonistic roles in appearance contradictory under a unified biological vision.